1. Field of the Invention
This invention is generally directed toward the treatment of food products and, more particularly, to a process and apparatus which applies ultrasonic energy to meat products immersed in an ozonated water environment.
2. History of the Related Art
In the food industry, and particularly the meat products industry, it is important that the products be free of harmful pathogens. In meat processing establishments approved by the United States Department of Agriculture (USDA), veterinarians check the temperatures of knife sterilizing vats, and also check animal carcasses, heads (especially the tongue), and some internal organs for signs of contamination and disease. In establishments approved by individual states, meat is also inspected by veterinarians.
Meat contamination typically occurs when the animal's gastro-intestinal (GI) tract is punctured, allowing feces and undigested food to spread to the carcass. In beef, contamination may also originate from the milk of spent dairy cows. If a meat inspector identifies any contamination from a punctured GI tract, the inspector will carve off that portion of the carcass which has come into contact with the contaminant. It has been estimated that approximately 4.5% of slaughtered animals have GI tracts which were punctured during evisceration. Any undigested food, fetes and/or milk may contain escherichia coli (E-coli), salmonella or other deadly bacteria or other less harmful bacteria, increasing the spoilage rate of meat products.
Unfortunately, the conventional inspection system has limitations. Animal carcasses pass an inspection station every few seconds, making it difficult for an inspector to locate every sign of contamination, consequently occasionally allowing contaminated carcasses to continue onto the meat processing states.
In response to recent E-coli reports, the federal government has been considering revision of its meat inspection procedures. Notices of "safe handling" have been added to packages of meat products and quick tests for E-coli presence have been developed. Recent proposed legislation in the House Agricultural Committee may give added power to inspectors to track the source of harmful contamination back to ranches or farms. This may allow identification of the source of the contamination.
Any processes to rid meat of harmful pathogens must take the conventional processing procedures into consideration. Animals used for food are cooled as fast as possible after slaughter. The carcasses are typically cut in half down the backbone to facilitate further handling. A beef half can weigh over 400 pounds and the typical market hog half weighs approximately 90 pounds. The half carcasses are graded and then processed into portions. Beef is cut into primals (wholesale cuts like loins, ribs, rounds, etc.) and boxed. Lower quality beef processed for hamburger is completely deboned and the meat is ground and usually frozen. A high percentage of E-coli bacteria is found in hamburger produced from spent cattle. Freezing does not kill E-coli or salmonella bacteria. Hog carcass halves are conveyed to a processing line where they are taken apart. The back leg (ham) is taken off with a saw. The front leg is removed, the ribs are pulled out and the belly is cut from the loin. The separated parts are then conveyed for further processing.
It is feasible to intercept carcass sections between the cooler (where the carcass is cooled from slaughter) and the processing line and subject the meat to pathogen eradication procedures. To be effective, however, these procedures should not disrupt the established process. The eradication procedures should be compatible with conventional meat processing steps and should also be cost-effective.
Several methods are known for treating food products, including meat products, with ozonated water to reduce the amount of pathogens contained on the surface of the food products (see for example U.S. Pat. Nos. 4,849,237 and 5,227,184 to Hurst and U.S. Pat. No. 4,827,727 to Caracciolo).
It is also known to apply ozone and sonic energy to sterilize and oxidize waste water as described in U.S. Pat. No. 4,003,832 to Henderson, et al. A method of sterilization for hospital instruments in which the instruments are sterilized by submersion in ultrasonically vibrated, ozonated water or other liquids such as alcohol or naphtha is described in U.S. Pat. No. 4,517,159 to Karlson.
Thus, there has been a need for a process and apparatus for treating meat products more effectively and efficiently than the known processes. If meat products are allowed to soak in water for too long of a time, the meat will absorb some of the water. Under current laws, beef products are not allowed to contain added water, and chicken products are only allowed to contain up to 8% added water. Thus, any effective process should not allow the meat products to soak in water for an extended time.
In view of the limitations and deficiencies associated with the known meat treating processes and apparatus, and particularly those intended to eradicate harmful pathogens, there is a need for an improved pathogen eradication process and apparatus which is cost-effective, time efficient and compatible with conventional processing lines.